An unexpected detection of bifurcated blue straggler sequences in the young globular cluster NGC 2173

Abstract

Bifurcated patterns of blue straggler stars in their color--magnitude diagrams have atracted significant attention. This type of special (but rare) pattern of two distinct blue straggler sequences is commonly interpreted as evidence of cluster core-collapse-driven stellar collisions as an efficient formation mechanism. Here, we report the detection of a bifurcated blue straggler distribution in a young Large MagellanicCloud cluster, NGC 2173. Because of the cluster's low central stellar number density and its young age, dynamical analysis shows that stellar collisions alone cannot explain the observed blue straggler stars. Therefore, binary evolution is instead the most viable explanation of the origin of these blue straggler stars. However, the reason why binary evolution would render the color--magnitude distribution of blue straggler stars bifurcated remains unclear.

9 pages, 8 figures, ApJ accepted

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Cited by in corpus (12)

• The "dynamical clock": dating the internal dynamical evolution of star clusters with Blue Straggler Stars
• Discovery of a double sequence of blue straggler stars in the core-collapsed globular cluster NGC 6256
• Discovery of a double Blue Straggler sequence in M15: new insight into the core-collapse process
• The double Blue Straggler sequence in NGC2173: a field contamination artefact
• UVIT Open Cluster Study. X. Rich Collection of Post Mass Transfer Systems in NGC 6791
• A Catalog of Periodic Variables in Open Clusters M35 and NGC 2158
• Blue straggler stars beyond the Milky Way. III. Detection of evolved blue straggler candidates in Large Magellanic Cloud clusters
• Decoding the bifurcated red-giant branch as a tracer of multiple stellar populations in the young Large Magellanic Cloud cluster NGC 2173
• The double Blue Straggler sequence in NGC2173: yes, a field contamination artefact!
• On the relationship between metallicity distributions of globular clusters and of circumgalactic gas
• Unveiling Bifurcated Blue Straggler Sequences in NGC 2173: Insights from Binary Evolution
• The double blue straggler sequence in NGC 2173: a field contamination artefact?